Question about AOC LM 720 17" Flat Panel LCD Monitor
My AOC LM 720 Flat Panel LCD Monitor has a problem... It only displays a bright white screen when its switched on. The bright white appears whether it is connected to the computer or not. The brightness controls have no effect and other monitors work fine when connected to the computer. It's got me a bit baffled, most of the LCD monitor fault-stories I've read are all back-light related but the back light in this one seems to be fine. Any ideas?
Try to check the capacitors
Posted on Jan 08, 2009
The all white screen indicated the 5 volt supply to the LCD panel is not there. The panel used the 5 volt supply to "black" out the picture. Usually the mini fuse on the panel circuit board has opened. 99% of the time there is a short in the LCD circuits that blows the fuse. Replacing the fuse will usually result in the fuse blowing again immediately.
Usually requires a panel replacement which is costly.
Posted on Apr 25, 2010
This is an old post but maybe this will help someone else......
I have sold a lot of these LM729's a few years back and now, out of warranty, they are starting to show these same symptoms. I was stumped at first but finally did some real testing on them and found that in every case it it the 1000uF capacitors that are faulty. Look at the board and you will see 2 capicitors, the barrel shaped components, that have 1000uF printed down the sides of them. Both of these should be replaced even if only one is bad because chances are the other will go soon as well. You can usually pick these up for under 2 bucks each at your local Radio Shack. Get ones rated for 35 volts (35V), the ones on the board are 16vols but I usually try to go a bit more robust when I replace capacitors. The rating is just how high the voltage can go so it's okay. They are usually more durable since they are to handle higher voltages. Just take the LM729 apart, remove the power board, desolder the capacitors, clean up the holes, (Be gentle in desoldering them, you don''t want to pull the things, you will pull off and possibly tear the copper foil pad that you need to solder the new cap to) Install the new capicitors minding the polarity, as in there is a MINUS sign on the capicitor and this must go in the hold with the matching MINUS sign. Solder the leads, clip the excess off. Reassemble and you'll probably find that LM729 working just fine! These are very good monitors and very rugged. AOC isn;t at fault for this failure. The Chinese have been making scads of bad capicitors for a few years now. Anymore, if there is an electronic failure it can be traced back to bad capicitors.
Posted on May 02, 2009
Sounds like bad video card drivers..Try updating the drivers from the manufacturer's website. Give us the details of your video card/ PC.
Or it could be monitor related. Open the monitor and check the power supply. Make sure there are no bad capacitors inside. If you find any replace them with new ones with same number or bigger capacity,
Posted on Apr 02, 2010
Hook up that monitor to another laptop or computer. If it works then its an issue with the vga port on your laptop. If the monitor still shows those lines then you know for sure the monitor is bad and it will have to be replaced.
Posted on May 15, 2011
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